On Wed, Dec 19, 2007 at 03:10:28PM -0500, linux-os (Dick Johnson) wrote:
>
>
> Here is a so-called BUG when trying to insert the following
> module into the kernel (2.6.22.1).
>
>
> BUG: unable to handle kernel paging request at virtual address 6814ec83
> printing eip:
> c016d013
> *pde = 00000000
> Oops: 0000 [#1]
> PREEMPT SMP
> Modules linked in: MemDev parport_pc lp parport nfsd exportfs lockd sunrpc
> iptable_filter ip_tables x_tables e1000 e100 mii nls_cp437 msdos fat dm_mod
> usbhid ff_memless uhci_hcd ehci_hcd video container button battery ac rtc
> ipv6 ext3 jbd ata_piix libata aic7xxx scsi_transport_spi sd_mod scsi_mod
> CPU: 0
> EIP: 0060:[<c016d013>] Not tainted VLI
> EFLAGS: 00010046 (2.6.22.1 #2)
> EIP is at kmem_cache_alloc+0x23/0x80
> eax: 00000000 ebx: 00000246 ecx: f8913300 edx: 6814ec83
> esi: 00000000 edi: f8913000 ebp: ef27e000 esp: ef27ff74
> ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068
> Process insmod (pid: 4593, ti=ef27e000 task=f614f550 task.ti=ef27e000)
> Stack: f8913300 00000000 00000000 f8913013 f7fff880 000000d0 00000000 ef27e000
> c012b907 ffffffff 00000000 c0140279 bffedc07 bffedc08 0807a018
> 00000000
> c0102b82 0807a018 000018c9 0807a008 00000000 00000000 bffeabc8
> 00000080
> Call Trace:
> [<f8913013>] init_module+0x13/0x48 [MemDev]
> [<c012b907>] blocking_notifier_call_chain+0x17/0x20
> [<c0140279>] sys_init_module+0xd9/0x140
> [<c0102b82>] sysenter_past_esp+0x5f/0x85
> =======================
> Code: 90 8d b4 26 00 00 00 00 83 ec 0c f6 c2 10 89 74 24 04 89 d6 89 7c 24 08
> 89 c7 89 1c 24 75 49 9c 5b fa 64 a1 04 20 47 c0 8b 14 87 <8b> 02 85 c0 74 25
> c7 42 0c 01 00 00 00 48 89 02 8b 54 82 18 53
> EIP: [<c016d013>] kmem_cache_alloc+0x23/0x80 SS:ESP 0068:ef27ff74
>
>
>
> Here is the code that causes the crash.
>
>
> #include <linux/autoconf.h>
> #include <linux/module.h>
> #include <linux/kernel.h>
> #include <linux/init.h>
> #include <linux/poll.h>
> #include <linux/mm.h>
> static const char devname[]="Device";
> #define NR_PAGES 0x10
>
> struct DMA {
> void *ptr;
> unsigned long addr;
> size_t len;
> };
> //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> //
> // The top-level object that gets allocated once, when the module is
> // installed.
> //
> struct INFO {
> struct file_operations fa; // Kernel connection
> struct semaphore dev_sem;
> struct DMA dma[NR_PAGES]; // Can map one megabyte
> uint32_t vm_start; // Where mmap() starts
> uint32_t pages; // Number of pages mapped
> atomic_t open; // Number of opens
> };
> //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> static struct INFO *info;
> //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> //
> // Initialize the module and return 0 if everything is okay.
> // Return a negative error-code if not.
> //
> static int32_t startup()
> {
> if((info = kmalloc(sizeof(struct INFO), GFP_KERNEL)) == NULL) {
> printk(KERN_ALERT"%s : Can't allocate memory\n", devname);
Missing space after KERN_ALERT?
> return -ENOMEM;
> }
> return 0;
> }
> //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> //
> // Cleanup the module in preparation for removal.
> //
> static void quit() {
> kfree(info);
> printk(KERN_INFO"%s : Module removed\n", devname);
> }
> MODULE_LICENSE("GPL");
> MODULE_ALIAS("MemDev");
> module_init(startup);
> module_exit(quit);
> //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
> Anybody have a clue why this should error out? Am I using
> some reserved names??? I got rid of __init and anything
> else that I thought could cause the fault, plus got rid
> of all the code!
--
Len Sorensen
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
